The Deir ez-Zor campaign, codenamed the al-Jazeera Storm campaign, was a military operation launched by the Syrian Democratic Forces (SDF) against the Islamic State (IS) in Syria's Deir ez-Zor Governorate in 2017 during the Syrian Civil War with the goal of capturing territory in eastern Syria, particularly east and north of the Euphrates river. The U.S.-led Combined Joint Task Force – Operation Inherent Resolve (CJTF–OIR) anti-ISIL coalition provided extensive air support while SDF personnel composed the majority of the ground forces; OIR special forces and artillery units were also involved in the campaign.Operation Inherent Resolve Official Twitter. Marched 25, 2019.

The ground campaign stalled and was paused in early 2018 due to the Turkish military operation in Afrin, but resumed on 1 May 2018 with the new phase named by the coalition as Operation Roundup. The third phase began on 10 September 2018 but was halted due to Turkish artillery attacks on SDF positions near the Syria-Turkey border on 31 October. The SDF and the coalition announced the resumption of the offensive on 11 November. After a series of steady successes following the capture of ISIL's Hajin stronghold, and a ten-day pause for civilian evacuations, the SDF launched its final assault on ISIL's final pocket of territory on 9 February 2019 and declared victory on 23 March, concluding the campaign.

The first phase of the campaign was concurrent with another SDF operation, the Raqqa campaign conducted against Raqqa, the Islamic State's then-capital city and main stronghold in Syria, as well as the Central Syria campaign, the Eastern Syria campaign, the Syrian Desert campaign, and the Deir ez-Zor offensive, in which Assad's Syrian Arab Army (SAA) was also capturing territory from the Islamic State; the Iraqi Army's Western Iraq campaign against ISIL was also underway.

Prelude On 25 August 2017, around 800 fighters from the Syrian Elite Forces defected to the SDF's Deir ez-Zor Military Council. On the same day, Ahmad Abu Khawla, commander of the Deir ez-Zor Military Council, announced that it would launch an offensive north of Deir ez-Zor within several weeks. Just before the start of the offensive, the SDF received a large amount of new weaponry and ammunition from the U.S.-led CJTF–OIR Coalition.

The campaign Initial phase

The SDF launched their ground operation on 8 September 2017 by attacking ISIL-held villages in the northern Deir ez-Zor countryside; on the next day, the campaign was officially announced in the al-Shaddadah Subdistrict, with the stated aim of expelling ISIL from all areas north and east of the Euphrates river. During the course of the next two days, the SDF rapidly advanced and captured numerous villages. According to pro-Syrian opposition media, this quick initial progress was due to ISIL forces retreating from areas that were difficult to defend in the face of heavy CJTF–OIR coalition airstrikes.

On 10 September 2017, the SDF fought its way into the fortified 'Industrial City', directly north of Deir ez-Zor city, while capturing more nearby villages. On 12 and 13 September, the SDF captured several locations at Deir ez-Zor's northern entrance (including the former Brigade 113 and al-Niran Battalion bases, the Sadkob station and part of the sheep market) as well as the silos and cotton storages in the Industrial City. Anti-ISIL forces also made further progress in the desert north of Deir ez-Zor, where it advanced 60 km. Despite these successes for the SDF, ISIL began offering stiffer resistance and began launching repeated counterattacks supported by VBIEDs in an attempt to stall the offensive and/or recapture territory.

Meanwhile, the SDF leadership stated that their forces would not attack Syrian government troops, which were simultaneously battling ISIL on the west side of the Euphrates. However, on 15 September, Ahmad Abu Khawla stated that the SDF would not allow Syrian government forces to cross the Euphrates. The next day, reportedly Syrian or Russian aircraft bombed SDF positions on the eastern bank of the Euphrates, injuring six SDF fighters. In response, CJTF–OIR stated that while they were putting their "full efforts into preventing unnecessary escalation among forces that share ISIS as our common enemy", "Coalition forces and partners always retain the right of self-defense". In this context, Institute for the Study of War expert Chris Kozak said that neither Russia nor the United States had an interest in escalating a conflict between themselves. "The real threat [is instead] that the partner forces on the groundthe SAA and the SDFcome close [to confrontation] before the US and Russia can slow them down." The Syrian government and the SDF were rivals in the Deir ez-Zor Governorate, as both sides wanted to capture the region's natural resources (most importantly its oil fields). On 17 September, the SDF captured a textile factory and a roundabout 7 km from Deir ez-Zor city.

Opening of a second front On 20 September, the SDF opened a second front against ISIL east of Deir ez-Zor, near the border with Iraq, and seized six villages alongside the M7 highway in quick order, advancing towards the oil-rich eastern countryside of Deir ez-Zor. On 21 September, Russia warned it would attack SDF fighters if provoked.Russia says will target U.S.-backed fighters in Syria if provoked, Reuters, 21 September 2017

As a response to the SDF advances, ISIL began to launch raids into SDF-held areas in southern al-Hasakah Governorate, reportedly ambushing and killing several SDF fighters on 21 and 24 September. ISIL counterattacks did little to impede the SDF offensive, however, with the SDF proceeding to capture the Al-Izba and Conoco gas fields, the Derro oil fields, and the Al-Bazikh mountain chain.

On 25 September, Russian aircraft, as well as Syrian and Russian artillery, bombarded SDF troops at the Conoco gas field, causing several casualties. The SDF responded by stating that "Russian and regime forces have mounted a treacherous attack against our forces," and that they would "use [our] legitimate right to self-defense". Further Russian bombing was reported on 27 September, with the SOHR stating 6 civilian casualties in Marat, to the east of the Euphrates River, opposite the Deir ez-Zor Military Airbase.Air strikes cause casualties and injuries in the east of the Euphrates River, and shelling kills one person in the vicinity of Al-Lataminah, SOHR, 27 September 2017 Iranian missile strikes on ISIL in the southern and eastern parts of the province were also reported on 24 September.Iran strikes IS bases on Syria-Iraq border with drone, AP, 24 September 2017

Despite the Russo-Syrian airstrike incidents, the SDF continued the offensive and pushed ISIL out of numerous villages over the following days. At al-Suwar, however, the SDF troops met fierce resistance on 24 September, and a heavy battle ensued; after six days of fighting the town finally fell. The SDF then attempted to further advance in al-Suwar's surroundings, while ISIL launched counterattacks to retake it.

Meanwhile, on 28 September, Yasser al-Dahla of The Gathering of al-Baggara Youth group was arrested by SDF military police on accusations of not effectively participating in the offensive and a "lack of military discipline". The Gathering of al-Baggara Youth denied these charges, and criticized the Deir ez-Zor Military Council of denying Euphrates Shield fighters who defected to the SDF to join the Gathering. Dahla reportedly threatened to cease his group's participation in the Deir ez-Zor offensive.

On 30 September, the SDF took control of the Jafra oil fields, which was one of the "most important sources of income for IS". Between 1 and 9 October, the SDF captured several more villages and repelled further ISIL counterattacks, with ISIL resistance in these areas being mostly light. This was due to ISIL relocating many of its fighters from its frontlines with the SDF in order to face the encroaching Syrian Army.

Between 9 and 10 October, the SDF captured four villages while advancing on the Euphrates river's eastern bank. Around a dozen SDF fighters were executed after ISIL recaptured al-Jazrah oilfield on 12 October. Many SDF fighters were killed and executed on 15 October after ISIL attacked their positions on the provincial border between al-Hasakah and Deir ez-Zor, infiltrating several checkpoints and outposts along the main road between Al-Salhiyah and Sor. Syrian military reports said on 19 October that the SDF had allowed Russian troops to enter and take control of Conoco gas field, despite both the SDF and the SAA trying to take control of al-Omar oil field from ISIL. Laila al-Abdullah, the spokesperson of the SDF, announced that they had captured the al-Omar oil field after a military operation in early hours of 22 October, and were clashing with ISIL fighters in an adjacent housing complex. SOHR stated that it had entered the oilfield after pro-Syrian government forces withdrew following an ISIL attack on them.

The SDF, later in the month, started advancing towards Abu Kamal and reportedly captured sites south of the oilfields. ISIL counterattacked on 29 October in an attempt to recapture the oilfield and was able to capture large territory along its perimeter while killing 6 SDF fighters. By November 2017, the SDF had reached the western outskirts of Markadah.

On 3 November, the SDF captured six villages while advancing on three different fronts. One village on the eastern bank of the Euphrates was captured near the Al-Busayrah axis, about southeast of Deir ez-Zor city. Two villages around northeast from the city and located near the border with Iraq were also captured. In addition, three villages east of Deir ez-Zor city and located on the bank of the Khabur river were captured by the SDF. On 6 November, the SDF cleared an ISIL pocket at Khabur after two SDF pincers met on both sides of the river and captured six villages, about east of Deir ez-Zor city.

Slowing down of the campaign

On 7 November, the SDF captured a village while advancing on the southwest along Khabur. The SDF captured the key town of Markadah on 8 November. On 12 November, the SDF captured al-Busayrah and all neighboring villages, thereby eliminating an ISIL pocket to the east of the Euphrates. The SDF captured the al-Tanak oil fields on the next day. On 14 November, the SDF pushed southwards along the river, capturing a village and killing 11 ISIL militants. By the next day, they had advanced within to the border with Iraq, according to the Syrian Observatory for Human Rights (SOHR). After ISIL lost Al-Qa'im and Abu Kamal to the Iraqi and Syrian Army, respectively, ISIL moved its de facto capital to the Syrian city of Hajin, in the Middle Euphrates Valley.

SDF forces, spearheaded by the Deir Ez-Zor Military Council, reached the Iraqi border on 25 November, through the northern countryside of Abu Kamal, effectively blocking the Syrian Army from the border crossings located north of the town. The United States Department of Defense (U.S. DoD) later announced in February 2018 that Shaykh Abu Anas al-Furati, a senior ISIL commander, was killed in an airstrike on Hajin on 27 November 2017. On 3 December 2017, the YPG declared that it had completely captured the eastern countryside of Deir Ez-Zor. The SDF captured three villages south of Deir Ez-Zor city on 9 December. During the clashes, the SDF was struck by a car bomb in a village, with Amaq News Agency reporting the deaths of 15 SDF fighters. Around this time it was reported that Russian airstrikes had helped Kurdish forces in their ground advances.